1. Field of the Invention
The present invention relates to a cleaning robot, and more particularly, to a dust detection method and apparatus which can increase the efficiency of a cleaning process by automatically detecting dust on a floor, appropriately adjusting a cleaning power of a cleaning robot, and appropriately modifying a cleaning path of the cleaning robot.
2. Description of Related Art
Recently, a variety of mobile robots, which generally include a driving means, sensors, and a travel controller and perform many useful functions while autonomously operating, have been developed. For example, a cleaning robot is a cleaning device that collects dust and dirt on the floor while autonomously moving about the surface without a user's control. For a more efficient cleaning process, the cleaning robot is required to correlate its cleaning power to the amount of dust and dirt on the floor.
Various dust detection techniques for a cleaning robot, which adjust the cleaning power of the cleaning robot based on a result of determining the amount of dust and dirt on the floor, are disclosed in U.S. Pat. Nos. 5,163,202, 5,233,682, and 6,023,814. More specifically, in U.S. Pat. No. 5,163,202, a light emitter and a light receptor are installed on a dust suction tube of a cleaning robot, and the amount of dust and dirt on the floor of a room is determined based on the amount of light received by the light receptor. In U.S. Pat. No. 5,233,682, the amount of dust and dirt determined based on the amount of light received by the light receptor, and the sizes of dust and dirt particles are also measured based on a total amount of time required for dust and dirt particles to pass through an optical passage. However, the dust detectability of these two patented techniques may deteriorate after a period of use because there is a high probability of impurities being accumulated at the light receptor and the light emitter. In order to solve this problem, U.S. Pat. No. 6,023,814 discloses a vacuum cleaner which includes a detection sensitivity correction unit installed at a suction passage.
All of the above patented techniques cannot determine whether dust particles exist on the floor until they draw the dust through a suction passage. In addition, the above patented techniques detect dust without considering the state of the floor, and thus, the efficiency of a cleaning process may deteriorate.